Pen-arm mounting



April 27, 1937. w. N. HUBBARD PEN ARM MOUNTING Filed May 19, 1936 INVENTOR WAL TER /V. HUB/9A RD ATTORNEY.

Patented Apr. 27, 1937 PATENT OFFICE PEN-ARM MOUNTING Walter N. Hubbard, Meriden, Conn., assignor to The Bristol Company, Waterbury, Comm, a cornotation of Connecticut Application May 19, 1936, Serial No. 80,505

13 Claims.

The invention relates to recording instruments comprising a recording pen or stylus movable in accordance with variations in a magnitude to be measured, and more particularly to mounting means for the pen-arm of such instruments.

One of the objects of the invention resides in the provision of mounting means whereby a penarm may be readily detachable and replaceable with respect to its actuating support.

Another object of the invention resides in the substantial elimination of friction between the pen and its recording surface, such, for example,

i as a vertically disposed record chart, by the provision of a mounting for the pen-arm whereby the latter is free to swing in a plane perpendicular to the recording surface, subject only to its own weight.

Still another object of the invention is to provide for a definite adjustment of the pen-arm whereby backlash may be eliminated without consequent binding.

The invention has for a further object the provision of mounting means which will admit of the incorporation therein of zero adjustment means for the pen-arm.

In addition, the invention has for an object the provision of a device embodying the aforesaid features and which will be rugged in construction, positive in action, readily fabricated and assembled, and which withal will be composed of a minimum number of parts.

In carrying out the invention, a pen-arm assembly is provided in which the deflected element, such as a recording pen-arm with pen of the conventional type, is carried upon a retaining member or bracket mounted upon the deflecting element of the recording mechanism. This retaining member, both in its construction and manner of attachment to the pen-arm, involves elements of novelty which form the basis of the present invention.

The present application is a continuation in part of a prior application Serial #754,586, filed by me November 24, 1934.

In its manufacture, the novel retaining member is struck up preferably from a single blank of resilient metal to afford at one side thereof an upstanding arm which may be perforated for pivotal and adjustable attachment to the deflecting member of the recording mechanism. The blank, furthermore, is provided with oppositely projecting and apertured or perforated end lugs which are also bent upwardly substantially at right angles to the body of the blank, while similar lugs formed by cutting U-shaped slots convex toward the central portion of said blank are bent downwardly substantially opposite the firstnamed lugs. These two pairs of lugs being thus resiliently supported will then cooperate about their lines of attachment to the body of the blank to provide in effect clamping elements of which the lower pair, also apertured or perforated, receive the conical ends of a transverse shaft to which the pen-arm is secured. By exerting pressure upon the pair of upwardly extending lugs, the lower pair may be sprung apart to permit insertion of the shaft, which shaf in its mounting therein will thus be oscillatabletoward and away from the record surface over which the pen-arm is designed to operate.

In order to maintain the desired tension on the shaft in the mounting of its ends in the respective apertures of the downwardly extending pair of lugs, as by regulating the spread of these lugs, there is inserted between the upper pair of lugs suitable means for exerting tension thereon and affording a desired degree of separation thereof. By this arrangement, the downwardly extending lugs will be proportionately sprung apart to afford the desired pressure adjustment upon the penarm shaft.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing, in which:

Fig. l is a front elevation showing the novel mounting means as adapted to a recording instrument.

Fig. 2 is a side elevation thereof.

Fig. 3 is a plan view of the blank from which said mounting means is struck up. 35

Fig. 4 is a plan view of the blank after having been struck up.

Fig. 5 is a fragmentary elevation illustrating a modification.

Fig. 6 is a horizontal section thereof taken on the line 6-6, Fig. 5; and Fig. 7 is a vertical section taken on the line 1--l, Fig. 6.

Referring to the drawing, more especially Figs. 1-4, H) designates a shaft forming part of the deflecting element of a recording instrument (not shown) and designed to impart an oscillating movement thereto as in rotating the same about a center line H. The extent of this deflection serves to provide a measure of a variable magnitude such as pressure, temperature, or an electrical quantity and to which the measuring instrument is adapted to respond.

Carried on the shaft III is an extension piece I l in the shape of an inverted U and upon which is pivotally mounted, as by means of a metal 5 eyelet i2 and in the axis of rotation H of the deflecting member II, the novel retainer member or bracket It for the pen-arm II of the recording instrument. The said arm carries a pen I of the conventional type, adapted to engage lightly the surface of a chart I1 and inscribe thereon a graphic record of its excursion within its limits of'travel in the plane of the chart. Pen-arm it at its upper end, moreover, is provided with a transverse pivot shaft it having conical ends designed to be supported by the retaining member I! as hereinafter set forth.

Tothisend,thesaidmemberisconstructed as follows and preferably of a single blank (Fig. 3) of resilient metal, such as sheet steel or the like. Two lugs 20 and 2!, having centrally disposed apertures 22 and 23 and extending from the opposite ends of the body portion 24 of the member, are bent upwardly therefrom and substantially at right angles thereto. Moreover, inward extensions 25 and 26 of these lugs are cut out of the said body portion, being bent downwardly therefrom substantially at right angles thereto to aflordafurtherpairoflugsalsoprovidedwith aperture 21 and 2!. In both instances, when the lugs are bent respectively upwardly and downwardly, the respective apertures thereof are designed to lie in axes substantially parallel to eachotherandtotheaxisofshaft "which is to be held in the said downwardly extending lugs as in lmving its conical ends fitting in the said apertures thereof.

Furthermore, the blank is provided with an arm element 30 which is bent upwardly from the body portion 24 thereof along one side, as indicated,

and substantially at right angles thereto, while at the opposite side a side portion Si is similarly bent upwardly to provide a reinforcement to the structure as formed.

It will be noted that, in this conformation, there will be formed a structure substantially rigid except that as the lugs 20 and 2i may be prmed toward each other through a small angle, as by pinching with the fingers, whereby slight bending will take place about the narrow sections joining these lugs to the main body of the structure; and since there will be no tendency for relative binding between the lugs 2| and 25 or the lugs 2i and 26, the downwardly extending lugs 25and26willbeslightlyseparated. Thisadmits of readily inserting the conical ends of the shaft ll in the apertures 22 and 23, respectively, so that upon release of the pressure upon the upwardly extending lugs, the shaft will be suitably positioned and held to the retaining member it.

An adjustment of this pressure upon the ends of shaft ll may be effected by positioning between saidlugs2l and2l aseparator stud or distance piece 32 having flat ends and threaded holes thereinwhichareadaptedtobeengagedby screws 38 and 34, respectively, passing through theapertures22and2lsuchthattheshanksof these screws will rest freely therein and their heads contact the outer surfaces of the respective lugs. By suitably threading these screws into the ends of the separating stud, the desired tension of the lugs 28 and 20 upon the shaft ends may behad. Atthesametimetheflatendsofstud 32 serveasstopsfor thelugs 2land2l,so that when the latter are gripped between the fingers of an operator with a view to separating the downwardlylugs25 and 26to release the penarm, movunent of such upwardly extending lugs will be limited, and straining of the retaining member II is avoided.

' For effecting a micrometer adjustment of the pen-arm i5 relative to extension piece Ii, the upper end of the arm 30 may carry a pivoted post 35 through which is then threaded a manually operable screw as engaging an abutment l1 pivoted upon the extension piece I I-. By rotating the screw 36, the relative angular position of the retaining member II, and with it the moving element of the measuring instrument, will be varied in the plane of deflection to provide thus the desired adjustment, as for the zero position of the pen I on the chart II.

Or, reference being had to Figs. 5-7, the adjustment of the pressln'e on the shaft ends may be effected by setting a single screw. Thus, there may be moimted between the two upwardly extending lugs ll and ll a bowed spring element 42 which is secured at its opposite ends to the respective lugs. Provision is made for varying the tension of this element through a vertically disposed screw 83 having its end 44 rotatably and slidably secured to the body portion 45 of th retaining member and its threaded portion work; ing in a nut it carried by the spring element. I y

head l'l projects beyond the said element to\ 25 be accessible for ready adjusting and is slotted in the usual manner to receive a screw driver or the like in effecting an adjustment of the tension on the pen-arm shaft 4. held between the downwardly extending lugs 40 and II. The downward excursion of the screw is limited by engagement of a shoulder ll, formed on its shank, with the said body portion; while its upward travel is restricted by a small washer i2 engaged by the peened-over end. This allows the screw freedom for a certain degree of longitudinal travel. Ordinarily the bowing action of the spring holds the screw in its lowest position, with shoulder II in engagement; and in this position the inward travel of the lower logs of the pen-holder is limited, so that the cross-piece or pen-arm shaft 48 is not too ti htly gripped Adjustment of the screw 3 serves to regulate to zero the compression exerted on the conical ends of the crosspiece without lost motion.

When the upwardly extending lugs are manually grasped. with a view to releasing the pen-arm. the spring is compressed, and the screw lifted ofl its seat, its upward limit of travel being determined by the washer 52 on its lower extremity. This prevents the lugs being compressed to an extent to strain the bending part of the holder and establish a permanent set in the metal. Thus, the travel of the lugs is definitely limited in both directions, with a free space for travel between, and these limits are, as in the previously described embodiment, established by portions of an adjustable screw member.

I claim:

1. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member mounted on said deflecting element and including a pair of resiliently supported. apertured, and downwardly disposed lugs, and a pen-arm having transversely disposed pivots adapted to engage in the respective apertures oi the downwardly dispom lugs, there being provided on the retaining member a further pair of lugs resiliently supported thereby and upwardly disposed for release of the pen-arm upon mutual approach of the said upwardly disposed pair of lugs.

2. A'mounting bracket for the pen-arm of a recording instrument, comprising a piece of metal embodying a flat body portion having end-apertured bendable lugs projecting upwardly from the body portion and substantially perpendicular thereto, and end-apertured lugs projecting downwardly and substantially perpendicularly from the body portion and lying respectively in planes common with said upwardly projecting lugs, and adapted to afiord for the pen-arm of the recording instrument supports bendable about their junction with the body portion.

3. A mounting bracket for the pen-arm of a recording instrument, comprising a piece of metal embodying a flat body portion having resiliently supported and end-apertured lugs projecting upwardly from the body portion and substantially perpendicular thereto, and resiliently supported and end-apertured lugs projecting downwardly and substantially perpendicularly from the body portion and lying respectively in planes common with said upwardly projecting lugs, and adapted to afford for the pen-arm of the recording instrument supports bendable about their junction with the body portion, and means fitting the apertures of the upwardly projecting lugs to limit the extent of outward movement thereof.

4. A mounting bracket for the pen-arm of a recording instrument, comprising a piece of metal embodying a flat body portion having resiliently supported and end-apertured lugs projecting upwardly from the body portion and substantially perpendicular thereto, and resiliently supported and end-apertured lugs projecting downwardly and substantially perpendicularly from the body portion and lying respectively in planes common with said upwardly projecting lugs, and adapted to afford for the pen-arm of the recording instrument supports bendable about their junction with the body portion, and a side element bent at an angle with the plane of said body portion whereby said body portion is rendered substantially rigid.

5. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said deflecting element and having two pairs of resiliently supported lugs, one of said pairs upwardly disposed and one pair downwardly disposed, and a pen-arm having a transverse part terminating in conical surfaces adapted to be engaged by one pair of said lugs and to be released therefrom by mutual approach of the other pair.

6. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said defleeting element and having two pairs of resiliently supported lugs, one of said pairs upwardly disposed and one pair downwardly disposed, a penam having a transverse part terminating in conical surfaces adapted to be engaged by one pair of said lugs and to be released therefrom by mutual approach of the other pair, and adjustable screw means for limiting the engagement of said one pair of lugs with said conical surfaces.

'1. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said deflecting element and having two pairs of resiliently supported lugs, one of said pairs upwardly disposed and one pair downwardly disposed, a pen-arm having a transverse part terminating in conical surfaces adapted to be engaged by one pair of said lugs and to be released therefrom by mutual approach of the other pair, and means for adjustably limiting the engagement of said one pair of lugs with said conical surfaces and including means afiording abutments for the respective upwardly disposed lugs for limiting the approach thereof.

8. In a pen-arm assembly for a recording in instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said deflecting element and having two pairs of resiliently supported apertured lugs, one of said pairs upwardly disposed and one pair downwardly disposed, a pen-arm having a transverse part terminating in conical surfaces adapted to be pivotally engaged by the apertures in one of said pm of lugs, a crosspiece supported between the other of said pairs of lugs, and screws passing through the apertures in the same and adjustably threaded into said crosspiece, whereby said screws may provide an adjustment of engagement between said conical suriaees and cooperating lugs.

9. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said deflecting element and having two pairs of resiliently supported apertured lugs, one of said pairs upwardly disposed and one pair downwardly disposed, a pen arm having a transverse part terminating in conical surfaces adapted to be pivotally engaged by the apertures in one of said pairs of lugs, a crosspieee supported between the other of said pairs of lugs, and screws passing through the apertures in the same and adjustably threaded into said crosspiece, whereby said screws may provide an adjustment of engagement between said conieal surfaces and cooperating lugs, together with means carried by the retaining member and engaging the deflecting element for adjusting said retaining member about its pivotal mounting.

10. A mounting bracket for the pen-arm of a recording instrument, comprising a piece of metal embodying a flat body portion having endapertured lugs projecting upwardly from the body portion and substantially perpendicular thereto and end-apertured lugs projecting downwardly and substantially perpendicularly from the body portion and lying respectively in planes common with said upwardly projecting lugs, and adapted to aflord for the pen-arm of the recording instrument supports bendable about their junction with the body portion, and means including a. resilient member fitting between the upwardly projecting lugs to limit the extent of operation thereof.

11. A mounting bracket for the pen-arm of a recording instrument, comprising a piece of metal embodying a flat body portion having endapertured lugs projecting upwardly from the body portion and substantially perpendicular thereto, and end-apertured lugs projecting downwardly and substantially perpendicularly from the body portion and lying respectively in planes common with said upwardly projecting lugs, and adapted to aiiord for the pen-arm of the recording instrument supports bendable about their junction with the body portion, and means including a resilient member fitting between the upwardly projecting lugs to limit the extent of operation thereof, together with means for varying the tension of said resilient means.

12. In a pen-arm assembly for a recording instrument having an element deflecting with -a 1o ends between the other oi said pairs of lugs, a

screw passing therethrough with its end rotatably and slidably secured in the retaining member, the spring having a threaded portion engaging with the threaded portion of the screw for vary- 15 ing its curvature.

13. In a pen-arm assembly for a recording instrument having an element deflecting with a measured magnitude: the combination of a retaining member pivotally mounted on said deflecting element and having two pairs 0! resiliently supported apertured lugs. one c! said pairs upwardly disposed and one pair downwardly disposed. a pen-arm having a transverse part terminatinginconical sln'facesadaptedtobeplvotally engaged bythe apertures in one oi said pairs of lugs, a bowed flat spring secured at its opposite ends between the other of said pairs oi. lugs, a screw passing therethrougb with its end rotatably and slidably secured in the retaining member and shouldered against its upper surface, and a stop on the said screw at the under side of said retaining member, the spring having a threaded portion engaging with the threaded portion of the screw for varying its curvature.

WALTER N. 

